Art for supporting driving of vehicles by recognizing images captured by car-mounted cameras have been well known. Such art includes devices which notify presence of junctions by recognizing stop lines painted on roads from images captured by car-mounted cameras, and devices which recognize pavement markers from images capture by car-mounted cameras and identify and display detailed current positions of the traveling vehicles.
Such art requires highly accurate image recognition for supporting safe driving of vehicles, and related art is disclosed in Patent Documents 1 and 2.
Patent Document 1 discloses a pavement marker detection device which recognizes running road of a vehicle from an image captured by a camera, sets a detection line within an image area of the vehicle running road recognized in the image captured by the camera, and detects a pavement marker according to changes in tones in the pixels on the detection line. In the pavement marker detection device disclosed in Patent Document 1, a range for performing recognition processing of a pavement marker within the captured image is limited to the self vehicle traveling area, to thereby reduce the processing time and prevent erroneous detection of an image area in a similar shape to that of the pavement marker, which is present outside the running road area.
Patent Document 2 discloses an image recognition device including a plurality of image capturing device for photographing various directions from a vehicle. The device selects one of the image capturing device according to self vehicle positional information, information regarding position and type of a pavement marker painted on the pavement near the self vehicle, weather information, brightness information, and vehicle speed information, and performs recognition of a pavement marker with respect to the image captured by the selected image capturing means. For example, in the case of a road in dark at night, a front-camera image in which a clear image can be captured by means of vehicle headlights is selected, and when the vehicle speed is high, a front-camera image in which can an object in an image can be captured for a long time is selected.
Patent Document 1: Japanese Unexamined Patent Publication 2006-24105
Patent Document 2: Japanese Unexamined Patent Publication 2007-147564